Generate KSP classes jar as output

Author: smocherla-brex

.bazelrc

@@ -3,6 +3,9 @@ common --enable_bzlmod=true
 common:rbe --java_runtime_version=11
 common:rbe --tool_java_runtime_version=11
 
+common --java_runtime_version=11
+common --tool_java_runtime_version=11
+
 build --strategy=KotlinCompile=worker
 build --test_output=all
 build --verbose_failures

MODULE.bazel

@@ -93,3 +93,4 @@ bazel_dep(name = "stardoc", version = "0.5.6", repo_name = "io_bazel_stardoc")
 bazel_dep(name = "rules_proto", version = "5.3.0-21.7")
 
 bazel_dep(name = "rules_testing", version = "0.5.0", dev_dependency = True)
+bazel_dep(name = "zlib", version = "1.3.1", dev_dependency = True)

src/main/kotlin/io/bazel/kotlin/builder/tasks/KotlinBuilder.kt

@@ -91,6 +91,7 @@ class KotlinBuilder
         REDUCED_CLASSPATH_MODE("--reduced_classpath_mode"),
         INSTRUMENT_COVERAGE("--instrument_coverage"),
         KSP_GENERATED_JAVA_SRCJAR("--ksp_generated_java_srcjar"),
+        KSP_GENERATED_CLASSES_JAR("--ksp_generated_classes_jar"),
       }
     }
 
@@ -250,6 +251,9 @@ class KotlinBuilder
           argMap.optionalSingle(KotlinBuilderFlags.KSP_GENERATED_JAVA_SRCJAR)?.let {
             generatedKspSrcJar = it
           }
+          argMap.optionalSingle(KotlinBuilderFlags.KSP_GENERATED_CLASSES_JAR)?.let {
+            generatedKspClassesJar = it
+          }
         }
 
         with(root.directoriesBuilder) {

src/main/kotlin/io/bazel/kotlin/builder/tasks/jvm/CompilationTask.kt

@@ -477,6 +477,21 @@ internal fun JvmCompilationTask.expandWithSourceJarSources(): JvmCompilationTask
     )
   }
 
+/**
+ * Produce a jar of classes generated by KSP.
+ */
+internal fun JvmCompilationTask.createdGeneratedKspClassesJar() {
+  JarCreator(
+    path = Paths.get(outputs.generatedKspClassesJar),
+    normalize = true,
+    verbose = false,
+  ).also {
+    it.addDirectory(Paths.get(directories.generatedClasses))
+    it.setJarOwner(info.label, info.bazelRuleKind)
+    it.execute()
+  }
+}
+
 private val Directories.stubs
   get() =
     Files

src/main/kotlin/io/bazel/kotlin/builder/tasks/jvm/KotlinJvmTaskExecutor.kt

@@ -139,6 +139,9 @@ class KotlinJvmTaskExecutor
           if (outputs.generatedKspSrcJar.isNotEmpty()) {
             context.execute("creating KSP generated src jar", ::createGeneratedKspKotlinSrcJar)
           }
+          if (outputs.generatedKspClassesJar.isNotEmpty()) {
+            context.execute("creating KSP generated classes jar", ::createdGeneratedKspClassesJar)
+          }
         }
       }
     }

src/main/protobuf/kotlin_model.proto

@@ -123,6 +123,8 @@ message JvmCompilationTask {
     string generated_class_jar = 7;
     // Source jar containing the generated KSP sources.
     string generated_ksp_src_jar = 8;
+    // The path to the jar containing the generated KSP classes
+    string generated_ksp_classes_jar = 9;
   }
 
   message Inputs {

src/test/data/jvm/ksp/BUILD

@@ -48,6 +48,14 @@ kt_ksp_plugin(
     ],
 )
 
+kt_ksp_plugin(
+    name = "generate_bytecode_plugin",
+    processor_class = "com.example.BytecodeGeneratorProcessor",
+    deps = [
+        "//src/test/data/jvm/ksp/bytecodegenerator/processor/src/main/com/example:processor",
+    ],
+)
+
 kt_jvm_library(
     name = "ksp_kotlin_resources",
     srcs = ["CoffeeAppModel.kt"],
@@ -140,9 +148,40 @@ kt_jvm_library(
     ],
 )
 
+kt_jvm_library(
+    name = "ksp_generate_bytecode",
+    srcs = ["BytecodeExample.kt"],
+    plugins = [":generate_bytecode_plugin"],
+    deps = [
+        "//src/test/data/jvm/ksp/bytecodegenerator/annotation",
+    ],
+)
+
+kt_jvm_library(
+    name = "ksp_bytecode_plugin_generates_no_classes_with_other_plugins",
+    # these files don't have relevant annotations, and don't generate the bytecode/generated classes
+    # from generate_bytecode_plugin
+    srcs = [
+        "CoffeeApp.kt",
+        "CoffeeBean.java",
+        "CoffeeMaker.kt",
+        "DripCoffeeModule.kt",
+    ],
+    plugins = [
+        ":generate_bytecode_plugin",
+        ":dagger",
+    ],
+    deps = [
+        "@kotlin_rules_maven//:com_google_dagger_dagger",
+        "@kotlin_rules_maven//:com_google_dagger_dagger_compiler",
+    ],
+)
+
 filegroup(
     name = "ksp",
     srcs = [
+        ":ksp_bytecode_plugin_generates_no_classes_with_other_plugins.jar",
+        ":ksp_generate_bytecode.jar",
         ":ksp_kotlin_resources.jar",
         ":ksp_kotlin_resources_missing_plugin.jar",
         ":ksp_kotlin_resources_multiple_plugins.jar",

src/test/data/jvm/ksp/BytecodeExample.kt

@@ -0,0 +1,6 @@
+package src.test.data.jvm.ksp
+
+import src.test.data.jvm.ksp.bytecodegenerator.annotation.GenerateBytecode
+
+@GenerateBytecode
+class BytecodeExample

src/test/data/jvm/ksp/bytecodegenerator/annotation/BUILD.bazel

@@ -0,0 +1,22 @@
+load("//kotlin:jvm.bzl", "kt_jvm_library")
+
+# Copyright 2018 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+package(default_visibility = ["//visibility:private"])
+
+kt_jvm_library(
+    name = "annotation",
+    srcs = ["GenerateBytecode.kt"],
+    visibility = ["//src/test:__subpackages__"],
+)

src/test/data/jvm/ksp/bytecodegenerator/annotation/GenerateBytecode.kt

@@ -0,0 +1,5 @@
+package src.test.data.jvm.ksp.bytecodegenerator.annotation
+
+@Target(AnnotationTarget.CLASS)
+@Retention(AnnotationRetention.SOURCE)
+annotation class GenerateBytecode